Everything You Need to Know about Narcissists, Psychopaths, and Abuse - click on this link: http://www.narcissistic-abuse.com/faq1.html
Most narcissists are prone to be angry. Their anger is always sudden, raging, frightening and without an apparent provocation by an outside agent. It would seem that narcissists are in a CONSTANT state of rage, which is effectively controlled most of the time. It manifests itself only when the narcissist's defences are down, incapacitated, or adversely affected by circumstances, inner or external.
Pathological anger is neither coherent, not externally induced. It emanates from the inside and it is diffuse, directed at the "world" and at "injustice" in general. The narcissist is capable of identifying the IMMEDIATE cause of his fury. Still, upon closer scrutiny, the cause is likely to be found lacking and the anger excessive, disproportionate, and incoherent.
It might be more accurate to say that the narcissist is expressing (and experiencing) TWO layers of anger, simultaneously and always. The first layer, of superficial ire, is indeed directed at an identified target, the alleged cause of the eruption. The second layer, however, incorporates the narcissist's self-aimed wrath.
(From the book "Malignant Self-love: Narcissism Revisited" by Sam Vaknin - Click on this link to purchase the print book, or 16 e-books, or 3 DVDs with 16 hours of video lectures on narcissists, psychopaths, and abuse in relationships: http://www.narcissistic-abuse.com/thebook.html)